A portion of the disclosure of this patent document contains material which is subject to copyright protection. The owner has no objection to the facsimile reproduction by any-one of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
The present invention relates to interactive instrumented models for teaching patient and self care, and more specifically, to an interactive instrumented breast model for training persons to perform a competent and thorough breast examination.
Due to the high incidence of breast cancer and generally poor proficiency of American women in breast self-examination (BSE), there is a need to train lay women to do thorough breast examination procedures. The broad objectives of the system are to educate users on breast cancer and breast care and to train breast examination techniques.
An American woman has a 1 in 8 chance of developing breast cancer in her lifetime. Among American women in 1998, more than 178,000 new cases of breast cancer were diagnosed and more than 43,000 persons died from the disease. These statistics make evident the significance of breast cancer. Because breast cancer is not curable, the key to survival is early detection and treatment.
There are three primary stages of breast cancer: localized, regional and distant. In the localized stage, lumps are small (less than 2 cm), and the cancer has not spread outside the breast. In the regional stage, lumps are medium sized (2 cm to 5 cm), and the cancer has spread to the lymph nodes in the armpit area. In the distant stage, lumps are large (greater than 5 cm), and the cancer has spread to other parts of the body. The five-year relative survival rate from cancer is highly dependent on the stage in which it is detected. For detection in the distant stage, survival rate is as low as 17%. The regional stage survival rate is around 61%. Finally, survival from breast cancer can be as high as 97% for detection in the localized stage. This leaves the important question of how breast cancer can be detected in the earliest stage.
Methods used for detection of breast cancer are breast self-examination (BSE), clinical breast examination (CBE) and mammography. BSE should be performed monthly by the woman herself. CBE should be performed yearly by a trained health care provider. There is no universal agreement on mammography screening intervals, and they vary with age. According to The American Cancer Society, women age 40-49 are recommended to have a routine screening mammogram every 1-2 years, and those over the age of 50 have an annual screening mammogram. Each method has benefits and deterrents; still, if all three are practiced according to guidelines, the optimum plan for earliest detection is in effect.
BSE is an attractive method for early detection of breast cancer for several reasons. It is performed at home by the woman; consequently, there is no cost associated with the exam. Second, there is only a one month time interval between screenings. It is also theorized that a woman would be highly sensitive to subtle changes in her own breast tissue. The combination of frequency of performance and familiarity of her own breast tissue suggests that breast cancer could be detected in the earliest stage.
CBE is also an important part of breast cancer detection and serves as an important complement to mammography. The cost of CBE is inexpensive relative to mammography. CBE may also be more sensitive than a mammogram in younger women because mammography is hindered in the presence of very dense breast tissue common in younger women.
Studies have shown that a major shortcoming of BSE and CBE is that exams are not performed optimally. In one study, two groups of lay women were tested on breast examination skills. The mean correct lump detection was only 25%. Another study on how well physicians could detect lumps with CBE showed only a 44% mean number of lumps detected. However, research has shown that training of examination techniques improves performance. Numerous studies have noted that a major determinant of the ability to detect masses lies not in the characteristics of the masses themselves, but in the thoroughness of the procedure undertaken to examine the breast tissue.
Usual training procedures for BSE include instructional videos, literature (books, magazine articles, pamphlets, shower cards, etc.) and one-on-one instruction. Of these methods, only the last involves providing feedback to the trainee on exam performance. Following training on silicone breast models, studies indicate that the women showed an increase in mean correct lump detection from 25% to approximately 50%. In addition, the mean time of examination increased. This illustrates the importance of training breast examination techniques to lay women and health care providers for effective breast examinations.
To be maximally effective, an examiner must be able to differentiate masses from surrounding tissue while using a pattern of search that ensures contact by the fingers with all portions of the breast tissue. In addition, this pattern of search should preferably minimize undue redundancy. Detailed training sequences have been developed for the various sensory-motor skills involved in breast examinations. The flats (from fingertips to first joint) of the three middle fingers should be used for the examination. The breast examination needs to cover the entire breast tissue: top to bottom from the collarbone to the bra line; side to side from center of chest area to armpit area; and from the surface of the breast tissue to deep along the chest wall. The examiner should use the flats of the fingers to perform palpations in dime-sized circles while applying three pressure levels: light, medium and deep. A light palpation disturbs only the skin surface and not the underlying breast tissue. A medium palpation examines the middle breast tissue. Finally, a deep palpation requires enough pressure to reach the breast tissue along the rib cage. The three pressure levels are necessary because lumps can be located at any level in the breast tissue. An expert examination covers the entire breast area using a non-redundant pattern of search while incorporating three levels of palpation pressure at each site.
There have been many breast examination patterns developed in order to achieve total coverage of the breast area. These include concentric circle, spoke and wedge, and vertical strip. The concentric circle pattern is the one most frequently taught in the United States. It consists of a series of concentric circles that begin in the upper outer quadrant of the breast and terminate at the nipple. The spoke and wedge pattern consists of radial spokes that begin on the perimeter of the conical breast and converge at the nipple. With either of these two patterns, the arm pit area is auxiliary and is typically examined as an additional step. The vertical strip pattern recognizes that the area of breast tissue is a rectangular region bordered by the clavicle, the sternum, the fifth rib and the mid-axillary line. This rectangular region is then divided into a series of vertical strips that are examined in sequence. Studies have been conducted to determine the effectiveness of these patterns. One such study showed that the vertical strip pattern provided more thorough coverage of the total breast area: 64.4% vertical strip vs. 38.9% concentric circle and 67.9% vertical strip vs. 44.7% spoke.
Because BSE and CBE are not performed optimally without proper training, there is a need for a user-friendly model training tool. that comprehensively trains breast examination techniques to lay women and health care providers. There is a further need to provide such trainees with immediate feedback in an easily readable, graphic format as to their examination techniques and the thoroughness of their examinations. There is still a further need to test and evaluate trainees under different scenarios to locate different size masses.
The instrumented breast model (IBM) of the present invention was developed to provide the necessary training to lay women and health care providers for the early detection of breast cancer. The IBM uses a silicone breast model equipped with sensors and data acquisition modules to collect data on examination performance, e.g., finger placement and palpation level (none, light, medium, and deep). This data is evaluated with a fuzzy logic algorithm, and feedback regarding the user""s performance is presented to the user in an easily readable graphical format. The IBM is user-friendly so that anyone who is literate and can use a computer mouse can operate the system easily.
Specifically, the IBM comprises a breast model in which a plurality of channels are drilled through the back such that the top of the channel comes within about xc2xc of an inch of the top surface of the breast model. One end of a piece of Kevlar string, which is knotted on both sides of a piece of gabardine fabric, is inserted into each channel and secured to the end of the channel. The second end of each piece of string is then attached to a pressure and position sensitive sensor that is able to detect and measure the displacement of the silicone breast model 102 during a practice examination. This displacement data is then converted into a graphical representation that allows the user to view his/her performance over the entire examined area.
The IBM of the present invention also provides the ability of a user to view various educational materials, including, but not limited to, training videos, tutorials, reference materials, and a breast cancer risk estimator.
There are many advantages for a lay person or health care provider using the IBM of the present invention. Due to the high incidence of breast cancer, the IBM provides for improved breast examinations, resulting in the early detection and treatment of breast cancer. In addition, a user""s examination methods are evaluated and displayed to the user in a very user-friendly graphical display, providing immediate feedback to the user on which portions of the examination need to be improved. The user interface for the IBM is windows based, thereby providing an easily accessible system that does not require any prior training.